It has been suggested that the vascular alterations found in inflamed gingiva may be of significance in the enhanced extension of the pathological process into the periodontium. The purpose of this investigation was to measured the changes in blood vascular volume occurring in gingiva with the onset of gingivitis and its resolution. Twenty‐six individuals participated in this study. Gingival biopsies were taken following a 21‐day experimental gingivitis, following resolution of a 21‐d experimental gingivitis and during a 6‐month experimental gingivitis and a 6‐month period of optimal oral hygiene. A total of 126 biopsies was obtained, from which 378 sections were cut at 2 μm for stereological analysis. At low magnification, reference volumes were estimated using point counting procedures and expressed as mm3 of gingiva per mm length of vestibular gingiva, in a vestibulo‐lingual plane. At higher magnification the ratio between the volume of vessels and connective tissue was calculated. The final results were expressed as mm3 of vessels per mm length of vestibular gingiva, in a vestibulo‐lingual plane. The mean vessel volume expressed per unit length of vestibular gingiva ranged from 0.010 to 0.024 mm3/mm. No statistically significant differences in vascular volumes were found between inflamed and non‐inflamed gingiva. It was concluded that the changes in vascular architecture during early gingivitis described in the literature had either taken place in the subjects prior to the time of experimentation or that any vascular changes (cytologic or functional) which had taken place may be compensatory for the changes in architecture described i